[Organic arboriculture researched: covering against weeds seems promising procedure]

agricultural research agriculture biologique arboricultura ornamental arboriculture arboriculture ornementale biological control cultural methods enemigos naturales ennemi naturel escarda farming systems farming systems research forest nurseries lutte biologique mode de culture natural enemies nutrition des plantes organic agriculture ornamental plants ornamental woody plants pepiniere forestiere plant nutrition plant protection plantas ornamentales plante ornementale plante ornementale ligneuse protection des plantes recherche agronomique viveros forestales weed control